The present invention relates to stator devices used in resolvers, motors, and other rotary electrical equipment, and more particularly to a stator device that is configured to prevent the breaking of stator jumper wires caused by the varnish that is used to fix stator coil wires.
FIG. 7 shows a VR (variable reluctance) resolver in which a rotor R is disposed on the inside of a prior art stator S. FIGS. 8-11 show other views of the prior art stator, portions thereof and other variations of portions of prior art stators. The stators shown in these figures essentially comprise a plurality of magnetic protuberances or teeth 2 disposed on the inner periphery of a stator body having a ring-shaped stator stack 1. A wire is wound around each of these magnetic teeth 2 to form the stator coil wire 3. As shown in FIGS. 7-9, an insulator 4 is formed on the outer and rear surfaces of the stator stack 1 and the magnetic teeth 2. A plurality of studs 5 project from the surface of the insulator 4. As shown in FIG. 9, wires 6 (hereinafter xe2x80x9cjumper wires 6xe2x80x9d) extend between stator coil wires 3 of adjacent magnetic teeth 2, extend behind studs 5 and rest on the outside of the studs 5. In practice, a continuous wire is wrapped around a magnetic protuberance 2, extended behind stud 5 and wrapped around at least the next adjacent magnetic protuberance 2. When the stator coil wires 3 are completely wound over the required number of continuous magnetic teeth 2, the wires are wrapped and fixed around output pins 8 that are provided. FIGS. 10 through 13 show views of examples of prior art studs 5.
In the prior art stator devices S discussed above, varnish is applied to the coil after the completion of coil winding in order to protect and fix the stator coil wires 3. Varnish is also applied to the jumper wires 6 that connect the stator coil wires 3. However, when varnish is applied, varnish accumulations 9, as shown in FIG. 14, tend to form in the corners of the jumper wires 6 and the studs 5. As a result, breaks in the jumper wires 6 can occur due to temperature fluctuations and the effect of differences in the coefficient of thermal expansion of the varnish accumulations 9 and the jumper wires 6.
Therefore, an object of this invention is to prevent varnish accumulations in a stator device.
Another object of this invention is to prevent wire breakage induced by temperature fluctuations by preventing the accumulation of varnish.
Another object of this invention is to prevent varnish accumulation by providing a space between the jumper wire and at least one of a supporting stud and a stator body.
Accordingly, in a first aspect of the present invention, a stator device is provided including a stator body having at least a pair of magnetic protuberances for supporting a wound wire, at least one stud disposed between the at least a pair of magnetic protuberances, a jumper wire extending behind the at least one stud and connecting the at least a pair of magnetic protuberances, and an abutment extending from the at least one stud to support the jumper wire and form a gap between the jumper wire and the stud to permit an applied varnish to flow out through the gap.
In the stator device configured as above, varnish accumulations do not form since the varnish flows toward the edge area of the stator from the gap that is formed between the stud and the jumper wire when the varnish is applied. Therefore, jumper wire breakage due to temperature variations can be effectively prevented.
In another aspect of the present invention, the abutment comprises first and second laterally spaced ribs extending from a wall of the stud. Each of the ribs may also extend from the stud wall in a shape resembling an approximately right-angled triangle, so that the jumper wire is supported by the oblique side [hypotenuse] of this approximately right-angled triangle. The oblique sides of the approximately right-angled triangles may be slightly concave to ensure that the wire will come to rest in the center area of the ribs.
By placing the wires on these ribs, a gap is formed between the jumper wire and the studs. A gap is also formed between the jumper wire and an edge of the stator body.
In still another aspect of the present invention, a single rib is provided approximately in the center area of each of the studs. The studs may extend from an insulator portion of the stator body, and the single rib may project from the stator body to an outer periphery of the insulator portion. The single rib may also have some of the other features of the laterally spaced ribs, as described above.
Further features and advantages of the invention will become evident to one skilled in the art upon reading of the detailed description of the invention, which is given below by way of example only and with reference to the accompanying drawings, and the scope of the invention will be indicated in the claims.